Improvement in pivot-bridges



T. C. GLABKE, A. B0 NZANU 8:. .I. G R FFEN.

Pivot-Bridges.

Patented Feb .11,1873.

WITNESSES. M

AM PHOTO-UTHUGRAPHIC ca Mflwearmzfs moms.)

UNITED STATES PATENT OFFICE.

THOMAS C. CLARKE, OF PHILADELPHIA, ADOLPHUS BONZANO, AND JOHN GRIFFEN, OF PH CENIXVILLE, ASSIGNORS TQ CLARKE, REEVES (10., OF PHILADELPHIA, PENNSYLVANIA.

vIMPROVEMENT IN PIVOT-BRIDGES.

Specification forming part of Letters Patent No. 135,776, dated February 11, 1873.

ification having been devised with the view,

in part, of adapting our said invention to [bridges not originally constructed in accordance therewith; the object of our invention being to readily relieve swing or pivot bridges from their corner-bearin gs, readily restore the same, and at the same time render the bridge self centering.

We attain these objects in a manner which will be best described by referring to the accompanyin g drawing, in which- Figure 1 represents a partial end view of the bridge, and Fig. 2 a side view of the end of the bridge.

A represents the end transverse girder of the bridge, this girder being in the present instance composed of the two beams to a, shown in Fig. 2 5 and 13 represents part of the lower chord of the bridge. and D part of one of the end posts. To the under side of the girder A, at each corner of the bridge, is secured a hanger, E, to which is hung a series of links, I) b, carrying at their lower ends rollers c e adapted to a foniulation-plate, G, on the pier H.

The links at each corner of the bridge are so connected to central operating mechanism that by manipulating the latter the whole of the links will be elevated simultaneously, so that the rollers will be free from contact with the foundationplate, and permit the bridge to rest on its central pivot only, or simultaneously lowered, so that they will form the sole support of the bridge when the latter is adjusted for the passage of trains.

It has not been deemed necessary to describe the mechanism by which the links are operated, as it is fully shown and described in the Letters Patent No. 128,115 granted to us on the 18th day of J une, A. D. 1872.

It will be .noted, however, that in the pres ent instance the said operating mechanism is applied to single links instead of to jointed links, forming toggles; and that the centering-plates are flat, with a rib at one side, instead of inclined toward the center, as in the plates described in said patent.

As shown in Fig. 1, the links I; are in a vertical position and serve as supports to the bridge, the latter being elevated above its pivot-bearing, and in a condition for the passage of trains. Should the turning of the bridge on its pivot be required, however, the four sets of links are moved simultaneously in the direction shown by the arrow in Fig. 1, when they will cease to support the bridge, and the latter rests on its central pivot only, and is free to be turned.

On turning the bridge back prior to its adjustment for the passage of trains the links are retained in an elevated position until they are above the foundation-plate G, when they are lowered by the operating mechanism, the rollers coming in contact with the said plates, so that, as the links gradually approach a vertical position, the four corners of the bridge must be gradually elevated until the links finally become the sole support of the bridge. In swinging the bridge round to its position, however, it is rarely that it can be arrested at the exact point necessary to in sure the coincidence of its rails with those of the main track, hence the foundation-plate is provided with a stop, h, adapted to the rollers carried by the links, shown in the perspective view, Fig. 3, so that on lowering the links the rollers will seek this stop, and finally names to this specification in the presence of two subscribing witnesses.

THOS. C. CLARKE. ADOLPHUS BONZANO. JOHN GRIFFEN. Witnesses to the signature of THOs. C. CLARKE:

WM. A. STEEL, LoUIs BosWELL. \Vitnesses to the signatures of ADOLPHUS BONZANO and JOHN GRIFFEN:

P. G. CAREY, JOHN BUKWALTER. 

